Thursday, July 26, 2012

Kudzu Bug moves closer to KY

Doug Johnson, Extension Entomologist

Title: First Report of Kudzu bug in Soybean [in Tennessee]

Author: Doug Johnson, Extension Entomologist

Figure 1. Kudzu bug adults on soybean

Dr. Scott Stewart, Extension Entomologist at the University of Tennessee’s research and education station in Jackson, TN has posted a blog concerning the first report of Kudzu bug on soybeans in Tennessee. I have included the entire text of his blog immediately below. Also, notice the link to the web site. I offer my thanks to Mr. Cam Kenimer, the ANR agent in Fulton Co. KY, for bringing this to my attention.

“ First Report of Kudzu bug in Soybean

Author: Scott Stewart, IPM Extension Specialist

I’ve had the first report of a soybean field in Tennessee being treated for kudzu bug. The field is located in East Tennessee (Polk County).

The threshold recommendation below is quoted directly from a website dedicated solely to this pest ( There is a lot of good information on this site. My counterparts in the Southeast have been working with this pest at a fevered pace for the past three seasons and generating a lot of good data. I would discourage any panic spraying. Kudzu bug infestations on soybean will almost certainly be isolated to a few fields in a very limited area. I do not expect problems in the larger soybean growing areas found in Middle and West Tennessee during 2012.

Threshold: “Kudzu bugs can be scouted using a 15-inch diameter sweep net. Kudzu bug populations can be extremely high, especially on field edges. We are suggesting a threshold of one immature kudzu bug per sweep. This suggested threshold is based on 2011 field trials where a single properly timed insecticide application preserved soybean yield. In the majority of trials we have conducted, nymphs usually appear at about the R-2 to R-3 growth stage. If adult numbers are extremely high (multiple adults per sweep) and soybeans are stressed, treatment should be considered; this is a judgment call but the idea is to avoid bug induced stress on soybeans that are also stressed for some other reason.”

Insecticide Selection: There is a limited list of insecticide that are well tested and specifically list kudzu bug on the label. Of these, Brigade 2E (bifenthrin), Hero (a premix including bifenthrin) and Endigo (a premix) appear to provide the best control. Some other pyrethroids such as Mustang Max, Declare and Karate appear to perform pretty well in limited testing, although Karate [sic same active ingredient as Warrior dwj] does not specifically list kudzu bugs on the label. Sevin, Orthene and Dimethoate also appear to perform reasonably well. These products should be used at or near the full labeled rate.

After looking at the data and talking with my counterparts, Brigade 2E or one of the other bifenthrin products at a rate of 6.0-6.4 oz/acre appears to be an obvious choice. It appears to provide the best bang for the buck. Not all insecticides will provide adequate control. The data I’ve seen suggests that Asana XL, Baythroid XL, Belay, Leverage 360, Lorsban are not good enough.”

To see the original text follow the link immediately below.

First, let me say that I concur completely with Dr. Stewart’s conclusions. In KY we should be even a bit further removed. Nevertheless, remember that this pest is not going to fly or walk to KY, but more likely to move on vehicles or in freight so its’ presence near the junction of I-75 and I-24 is important to us.

Figure 2. Location of Polk Co. TN
At present, this is certainly the closest Kudzu bug infestation on soybean to Kentucky. The county from which this is reported (Polk) is in the southeastern portion of TN and is bordered on the east by North Carolina and on the south by Georgia. Of particular interest with respect to eastern / central KY, soybean (also garden beans / peas) production, this county’s western border is only about 10 miles east of I-75. Additionally, Polk Co. TN is only one county removed from the junction of I-75 and I-24. The pest has already been collected from Kudzu in Marion Co. TN which is astride I-24. Interstate-24, of course, goes through the heart of soybean production in western Kentucky. Because of interstate access, this infestation should be of as much interest to Kentucky producers as it is to those in Tennessee.

There is no reason to panic at this point. As Dr. Stewart indicates for TN, we are quite unlikely to see any problem with this pest in Kentucky soybeans in 2012. I think we are much too far along. The story in 2013 may be a different.

Photo Credit Figure 1: Philip Roberts, Univ. GA.,
Photo Credit Figure 2: Wikipedia

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